You both are right, precautions are only taken by responsible gamblers to prevent them from becoming addicted and also to prevent losing so much. It's very possible that one can lose $20k in a day in they continue gambling with high stake. For example, if they stake $1k per person bet, they only need to lose 10 times for all the money to go to the casino but if they are staking with small amount like $5 per bet, they will last more longer. So, precautions can be taken to reduce losses but not to determine chance of winning.
You are both on the right track, precautions are taken only by responsible players to avoid becoming addicted and to avoid losing too much, you have to live and to live you need money. It is very possible to lose $20k in a day if you keep playing with high stakes. So, precautions can and should be taken to reduce losses.